Patched 1 regulates Smoothened by controlling sterol binding to its extracellular cysteine-rich domain

Maia Kinnebrew, Rachel E. Woolley, T. Bertie Ansell, Eamon F.X. Byrne, Sara Frigui, Giovanni Luchetti, Ria Sircar, Sigrid Nachtergaele, Laurel Mydock-McGrane, Kathiresan Krishnan, Simon Newstead, Mark S.P. Sansom, Douglas F. Covey, Christian Siebold, Rajat Rohatgi

Research output: Contribution to journalArticlepeer-review

Abstract

Smoothened (SMO) transduces the Hedgehog (Hh) signal across the plasma membrane in response to accessible cholesterol. Cholesterol binds SMO at two sites: one in the extracellular cysteine-rich domain (CRD) and a second in the transmembrane domain (TMD). How these two sterol-binding sites mediate SMO activation in response to the ligand Sonic Hedgehog (SHH) remains unknown. We find that mutations in the CRD (but not the TMD) reduce the fold increase in SMO activity triggered by SHH. SHH also promotes the photocrosslinking of a sterol analog to the CRD in intact cells. In contrast, sterol binding to the TMD site boosts SMO activity regardless of SHH exposure. Mutational and computational analyses show that these sites are in allosteric communication despite being 45 angstroms apart. Hence, sterols function as both SHH-regulated orthosteric ligands at the CRD and allosteric ligands at the TMD to regulate SMO activity and Hh signaling.

Original languageEnglish
Pages (from-to)eabm5563
JournalScience Advances
Volume8
Issue number22
DOIs
StatePublished - Jun 3 2022

Fingerprint

Dive into the research topics of 'Patched 1 regulates Smoothened by controlling sterol binding to its extracellular cysteine-rich domain'. Together they form a unique fingerprint.

Cite this